Just to add to the discussion of importing songs and backing up, I’ll throw out a way I’ve been using (notice I’m not suggesting it’s the only way) my song app on an iPad.
First, any file like a PDF (not text files though) that I want to store in the app I first store on a directory of files on the cloud (Dropbox in my case) that contains all the files that I’ve put in the app.
From what I understand, on IOS, external files like PDFs are not physically stored within the app. They are in a files area that the app builds references to. So when I backup my app, everything (text files included) in the app gets copied except for external PDFs and the like. The references to the external files get backed up. I store that app backup file on a directory on the cloud as well and keep several iterations.
Assuming a major crash and I have to resurrect the app and its files from scratch, I restore the backup but all the external files will be missing. So I will attach the iPad to my computer and go into iTunes. It will list the song app along with an area that lists all the files that have been attached to the app. In this case, I’ll assume the list is empty. So I open Windows Explorer, open up the directory on the cloud that has all my files that should exist in the app, select all those files and drag/drop them into the app’s File area in iTunes. Since the app references files by name, all my attached files will now appear in the app in one step.
If I need to add a single file, I can point to it in Dropbox and do an “Open In” (or whatever they’re calling it in IOS v13) my song app to transfer the file. I only use iTunes when I need to do bulk copies.
This approach for storing the external files (PDFs, Word) in a separate area on the cloud from which I import them into the app, also allows me to spin off copies of any sub set of files to whomever, independent of any app it’s stored in.
Furthermore, if the app or IOS by some weird circumstance corrupts the file, I’ve got an independent backup. I also may have an editable Word version of the file along with a generated PDF file in the Dropbox directory. PDFs are typically much smaller in size so I may weed out the Word files when copying over to the app. This is one area that I didn’t like about OnSong, it prefers to store files in its own proprietary format. All my song files are text, PDF, or Word or Open Office format. And yes Word can get corrupted, but being so small a file for an individual song, that’s unlikely.
Hope this makes sense.